Quality management has emerged as a management paradigm for enhancing organizational performance. Despite extensive research in quality management, little empirical research has been done on this in an international context, especially in the Middle East. This study attempts to investigate: (1) the relationship among quality management practices; and (2) the effect of quality management practices on internal and external quality results in the petroleum industry. Data was collected from project managers/consultants in the petroleum industry in Iran. The results show that top management support is the major driver of quality management, which significantly correlates with other quality management practices. It was also found that customer orientation is not significantly correlated with external quality results. Top management support, employee training, and employee involvement as the three statistically significant variables in explaining the variability in internal quality results. Furthermore, it was found that internal quality results was statistically significant in explaining the variability of external quality results.